Improved protocol for asymmetric, intramolecular heteroatom Michael addition using organocatalysis: Enantioselective syntheses of homoproline, pelletierine, and homopipecolic acid

An improved protocol for the construction of enantioenriched pyrrolidine, indoline, and piperidine rings using an organo-catalyzed, intramolecular heteroatom Michael addition is described. Application to the enantioselective synthesis of homoproline, homopipecolic acid, and pelletierine has been accomplished.